package me.ezitku.base.utils;

/**
 * Created by Elbiz on 12/2/2016.
 */

public class SHA1Utils {
	private static final boolean hexcase = false;
	private static final String b64pad = "=";
	private static final int chrsz = 8;

	/**
	 * encrypt String value
	 * @param s
	 * @return
	 */
	public static String hex_sha1(String s) {
		s = (s == null) ? "" : s;
		return binb2hex(core_sha1(str2binb(s), s.length() * chrsz));
	}

	public static String b64_hmac_sha1(String key, String data) {
		return binb2b64(core_hmac_sha1(key, data));
	}

	public static String b64_sha1(String s) {
		s = (s == null) ? "" : s;
		return binb2b64(core_sha1(str2binb(s), s.length() * chrsz));
	}

	private static String binb2b64(int[] binarray) {
		String tab = "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz0123456789+/";
		String str = "";
		binarray = strechbinarray(binarray, binarray.length * 4);

		for (int i = 0; i < binarray.length * 4; i += 3) {
			int triplet = (((binarray[i >> 2] >> 8 * (3 - i % 4)) & 0xff) << 16)
				  | (((binarray[i + 1 >> 2] >> 8 * (3 - (i + 1) % 4)) & 0xff) << 8)
				  | ((binarray[i + 2 >> 2] >> 8 * (3 - (i + 2) % 4)) & 0xff);

			for (int j = 0; j < 4; j++) {
				if (i * 8 + j * 6 > binarray.length * 32) {
					str += b64pad;
				} else {
					str += tab.charAt((triplet >> 6 * (3 - j)) & 0x3f);
				}
			}
		}

		return cleanb64str(str);
	}

	private static String binb2hex(int[] binarray) {
		String hex_tab = hexcase ? "0123456789abcdef" : "0123456789abcdef";
		String str = "";

		for (int i = 0; i < binarray.length * 4; i++) {
			char a = hex_tab.charAt((binarray[i >> 2] >> ((3 - i % 4) * 8 + 4)) & 0xf);
			char b = hex_tab.charAt((binarray[i >> 2] >> ((3 - i % 4) * 8)) & 0xf);
			str += (new Character(a).toString() + new Character(b).toString());
		}

		return str;
	}

	private static String binb2str(int[] bin) {
		String str = "";
		int mask = (1 << chrsz) - 1;

		for (int i = 0; i < bin.length * 32; i += chrsz) {
			str += (char) ((bin[i >> 5] >>> (24 - i % 32)) & mask);
		}

		return str;
	}

	private static int bit_rol(int num, int cnt) {
		return (num << cnt) | (num >>> (32 - cnt));
	}

	private static String cleanb64str(String str) {
		str = (str == null) ? "" : str;
		int len = str.length();

		if (len <= 1) {
			return str;
		}

		char trailchar = str.charAt(len - 1);
		String trailstr = "";

		for (int i = len - 1; i >= 0 && str.charAt(i) == trailchar; i--) {
			trailstr += str.charAt(i);
		}

		return str.substring(0, str.indexOf(trailstr));
	}

	private static int[] complete216(int[] oldbin) {
		if (oldbin.length >= 16) {
			return oldbin;
		}

		int[] newbin = new int[16 - oldbin.length];

		for (int i = 0; i < newbin.length; newbin[i] = 0, i++)
			;

		return concat(oldbin, newbin);
	}

	private static int[] concat(int[] oldbin, int[] newbin) {
		int[] retval = new int[oldbin.length + newbin.length];

		for (int i = 0; i < (oldbin.length + newbin.length); i++) {
			if (i < oldbin.length) {
				retval[i] = oldbin[i];
			} else {
				retval[i] = newbin[i - oldbin.length];
			}
		}

		return retval;
	}

	private static int[] core_hmac_sha1(String key, String data) {
		key = (key == null) ? "" : key;
		data = (data == null) ? "" : data;
		int[] bkey = complete216(str2binb(key));

		if (bkey.length > 16) {
			bkey = core_sha1(bkey, key.length() * chrsz);
		}

		int[] ipad = new int[16];
		int[] opad = new int[16];

		for (int i = 0; i < 16; ipad[i] = 0, opad[i] = 0, i++)
			;

		for (int i = 0; i < 16; i++) {
			ipad[i] = bkey[i] ^ 0x36363636;
			opad[i] = bkey[i] ^ 0x5c5c5c5c;
		}

		int[] hash = core_sha1(concat(ipad, str2binb(data)), 512 + data.length() * chrsz);

		return core_sha1(concat(opad, hash), 512 + 160);
	}

	private static int[] core_sha1(int[] x, int len) {
		int size = (len >> 5);
		x = strechbinarray(x, size);
		x[len >> 5] |= 0x80 << (24 - len % 32);
		size = ((len + 64 >> 9) << 4) + 15;
		x = strechbinarray(x, size);
		x[((len + 64 >> 9) << 4) + 15] = len;

		int[] w = new int[80];
		int a = 1732584193;
		int b = -271733879;
		int c = -1732584194;
		int d = 271733878;
		int e = -1009589776;

		for (int i = 0; i < x.length; i += 16) {
			int olda = a;
			int oldb = b;
			int oldc = c;
			int oldd = d;
			int olde = e;

			for (int j = 0; j < 80; j++) {
				if (j < 16) {
					w[j] = x[i + j];
				} else {
					w[j] = rol(w[j - 3] ^ w[j - 8] ^ w[j - 14] ^ w[j - 16], 1);
				}

				int t = safe_add(safe_add(rol(a, 5), sha1_ft(j, b, c, d)), safe_add(safe_add(e, w[j]), sha1_kt(j)));

				e = d;
				d = c;
				c = rol(b, 30);
				b = a;
				a = t;
			}

			a = safe_add(a, olda);
			b = safe_add(b, oldb);
			c = safe_add(c, oldc);
			d = safe_add(d, oldd);
			e = safe_add(e, olde);
		}

		int[] retval = new int[5];

		retval[0] = a;
		retval[1] = b;
		retval[2] = c;
		retval[3] = d;
		retval[4] = e;

		return retval;
	}

	private static void dotest() {
		String key = "key";
		String data = "data";
		System.out.println("hex_sha1(" + data + ")=" + hex_sha1(data));
		System.out.println("b64_sha1(" + data + ")=" + b64_sha1(data));
		System.out.println("str_sha1(" + data + ")=" + str_sha1(data));
		System.out.println("hex_hmac_sha1(" + key + "," + data + ")=" + hex_hmac_sha1(key, data));
		System.out.println("b64_hmac_sha1(" + key + "," + data + ")=" + b64_hmac_sha1(key, data));
		System.out.println("str_hmac_sha1(" + key + "," + data + ")=" + str_hmac_sha1(key, data));
	}

	public static String hex_hmac_sha1(String key, String data) {
		return binb2hex(core_hmac_sha1(key, data));
	}

	private static int rol(int num, int cnt) {
		return (num << cnt) | (num >>> (32 - cnt));
	}

	private static int safe_add(int x, int y) {
		int lsw = (x & 0xffff) + (y & 0xffff);
		int msw = (x >> 16) + (y >> 16) + (lsw >> 16);

		return (msw << 16) | (lsw & 0xffff);
	}

	private static int sha1_ft(int t, int b, int c, int d) {
		if (t < 20)
			return (b & c) | ((~b) & d);

		if (t < 40)
			return b ^ c ^ d;

		if (t < 60)
			return (b & c) | (b & d) | (c & d);

		return b ^ c ^ d;
	}

	private static int sha1_kt(int t) {
		return (t < 20) ? 1518500249 : (t < 40) ? 1859775393 : (t < 60) ? -1894007588 : -899497514;
	}

	private static boolean sha1_vm_test() {
		return hexcase ? hex_sha1("abc").equals("a9993e364706816aba3e25717850c26c9cd0d89d") : hex_sha1("abc").equals(
			  "a9993e364706816aba3e25717850c26c9cd0d89d");
	}

	public static String str_hmac_sha1(String key, String data) {
		return binb2str(core_hmac_sha1(key, data));
	}

	public static String str_sha1(String s) {
		s = (s == null) ? "" : s;

		return binb2str(core_sha1(str2binb(s), s.length() * chrsz));
	}

	private static int[] str2binb(String str) {
		str = (str == null) ? "" : str;

		int[] tmp = new int[str.length() * chrsz];
		int mask = (1 << chrsz) - 1;

		for (int i = 0; i < str.length() * chrsz; i += chrsz) {
			tmp[i >> 5] |= ((int) (str.charAt(i / chrsz)) & mask) << (24 - i % 32);
		}

		int len = 0;
		for (int i = 0; i < tmp.length && tmp[i] != 0; i++, len++)
			;

		int[] bin = new int[len];

		for (int i = 0; i < len; i++) {
			bin[i] = tmp[i];
		}

		return bin;
	}

	private static int[] strechbinarray(int[] oldbin, int size) {
		int currlen = oldbin.length;

		if (currlen >= size + 1) {
			return oldbin;
		}

		int[] newbin = new int[size + 1];
		for (int i = 0; i < size; newbin[i] = 0, i++)
			;

		for (int i = 0; i < currlen; i++) {
			newbin[i] = oldbin[i];
		}

		return newbin;
	}

	public static void main(String args[]) {
		System.out.println("admin's SHA1 value：" + hex_sha1("admin") + ",length=" + hex_sha1("admin").length());
	}
}
